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A. SPENGE.

PURNAGE FOR WATER HEATERS.

No. 880,297. Patented Mar. 27, 1888.

UNITED; STATES PATENT rricn.

AROHIBALD SPENOE, OF MONTREAL, QUEBEC, CANADA, ASSIGNOR TO THE I NATIONAL HOT WATER HEATER COMPANY, OF BOSTON, MASSACHU- SETTS.

FURNACE FOR WATER-HEATERS.

SPECIFICATION forming part of Letters Patent No. 380,297, dated March 27,1888.

Application filed January 31. 1888. Serial No. 262,539. (No model.)

To ctZZ whom it may concern.-

Be it known that I, ARCHIBALD SPENOE, a subject of the Queen of Great Britain, residing at the city oi Montreal, in the district of Montreal and Province of Quebec, Canada, have invented new and usefullmprovementsin Furnaces for Water-Heaters; and I do hereby declare that the following is a full, clear, and exact description of the same.

This invention has reference to the construction of furnaces for water-heaters, and, as shown in the drawings, is particularly adapted to the water-heater invented by me, for which Letters Patent of the United States were granted 8th day of March, A. D. 1887, No. 359,105.

The object of the presentinvention is to pro duce waterspaces (round or about the fire) having extended surface almost equal to the amount of surface for the fire to act upon when formed by circular tubes, without the necessity, as in the case where circular tubes are used, of having an outer casing to prevent the products of combustion from passing out between the tubes; thereby also a saving in the cost of construction is effected, and a form of watercasing is given which is remarkably exempt from becoming cracked or broken by unequal expansion.

In the drawings hereunto annexed similar letters of reference indicate like parts.

s Figure 1 is a'plan of a furnace embodying my invention. Fig. 2 is a section on line 00 m in Fig. 3. Fig. 3 is a front elevation of the furnace shown in Fig. 1. Fig. 4 is a section on line :19, Fig. 2. Fig. 5 is a section on line 1 in Fig. 1, which is the same in position as line y in Fig. 2.

The furnace in this case consists ofa top hollow ring, a, and a bottom hollow ring, I). These are cast integral with a central tubular part, c. The tubular part 0 consists of tubes of the double tubular form shown at l in Fig. 2. By making them in this form a considerable saving is effected in the labor of molding, while they give an almost equal amount of surface acted upon by the fire that circular tubes would give. The tubes 1 are connected together by short bridge-pieces (Z. By making these bridgepieces short the heat that is im'partedto them by the fire is, nearly all of it, by conduction through the metal, imparted to the water in the tubes, the whole forming a complete casing not requiring any other outer casing to prevent the products of combustion from es- Gaping.

Another advantage in constructing the center part, c, composed of the double tubular form 1 and bridges d, is that by practical use it is found that this form is very remarkably exempt from becoming cracked by the unequal expansion of the metal (caused by the lire acting unequally on various portions of it) as compared with the other forms of furnaces at present in use.

e is the fire hole opening. f are the inlet-wa- 6:, ter pipes to the bottom ring, b, and g is the outlet by which the water circulates or passes from the furnace-casing above described to the desired sections of water-heater situated above the fire.

Although, as above described and as shown in the drawings, the furnace-casing is a circular one, yet it will be readily understood that my invention may be equally well applied to angular casings.

What I claim, and wish to secure by Letters Patent, isas follows:

The combination, in a fire-box casing, of the upper and lower rings of hollow form and having inlet and outlet, with the central tubu- 8o lar portion composed of the double tubular form and bridge-pieces, the whole substantially as described.

ARCHIBALD SPENOE-J Witnesses:

CHARLES G. G. Srnrson, W. E. Funenn. 

